You need 40mm-Lock-Swivel-Caster-004 to have your office desk, equipment or even a machine to easily roll them around. Diameter of the caster wheel is a metric standard 40mm that is equal to 1.575" inch with imperial units. Dimensions of the caster wheel is 40mm (1.575" inch). The caster dimensions heightwise is 257mm/10.118" inch. This wheel caster can be mounted using a with the dimensions of 47mm x 47mm and holes distance of 129mm x 74mm. Rolling with a wheel core material of Acrylonitrile Butadiene Styrene (Plastic) and a Acrylonitrile Butadiene Styrene (Plastic) tire rolled over Roller bearing. Each caster will carry the load of 55 lb and is Swivel and Upper Locking type. The temperature range is -40 to 180 F. Remember, you will have to buy the 40mm-Lock-Swivel-Caster-004 in order to have it :).